<February 25, 2007>
Began Right Flap Riveting
The days that you rivet are always great. It means that you are done with all the prep work and that at the end of the day you will usually have something to show for all your work. I started the day by building myself a set of v-shaped cradles to hold the flaps still while riveting. I don't really see how you could rivet the flaps without them. Once I was happy with my v-blocks, things started going together rather quickly. The flap instructions are rather vague, but by now I should be able to figure out what needs to be done.
I cut two similar sized pieced of 3/4" MDF, screwed them together, and sanded the bottom uniform on the disc sander. Using a square, I drew a centerline down the pieces of wood and marked the shape of the flap onto the top piece of wood. Using the band saw I cut out the center "V" and removed the screws to leave me with two identical cradles.
I mounted both cradles to additional pieces of MDF, drew a straight line on the table and then screwed the assemblies to the table using the line as a guide to keep them aligned with one another. I used some duct tape to cover the inside edges of the cradles to reduce the chance of scuffing the skins.
For my first trick, I riveted the FL-706Bs to the rib and attached the nutplate. I am trying my best to conform to the rule of keeping the shop head on the thicker material.
I then riveted the FL-706As to the spars, again with the shop head on the thicker material. I made sure not to rivet the inboard three holes where the rib will attach. Those holes get riveted with LP4-3s when riveting the spar in place.
To keep everything straight I reassembled the flap and put it into the v-blocks. It fit like a glove. Ooops, I am getting ahead of my self here. During the reassembly I squeezed the rivets attaching the rear flange of the ribs to the bottom skin's quasi-spar, making sure spacers were used where needed. With the flaps now in the cradles I removed the clecos holding the spar in place and removed the spar to allow access to the inside of the flap.
This was tight, but I figured it out. I was a little concerned about dropping the bucking bar inside the flaps but I had what I think was a bright idea. I cut myself a 1"x6" piece of 1/2" thick foam that I had laying around the shop. The foam was some scrap floor mat I had laying around. I was then able to lay the foam along the rear spar and use it to brace or hold the bucking bar in position without scratching up the inside of the flap.I reached down into the flap an applied pressure to the bucking bar while riveting but I didn't have to worry about holding the bucking bar up onto the tail of the rivet. Am I making any sense here? You can sort of see what I mean in the picture. My tungsten bucking bar is being held into position (vertically) but the foam below. Areas of the bar are wrapped in tape so it doesn't scratch anything while riveting. This foam only helps with the bottom row of rivets, but that is where the flap is its narrowest and where it seemed to be needed most.
Before calling it quits for the night, I managed to get the all the rivets shot on the bottom of the right flap.